\documentclass{article}
\usepackage{amssymb,amsmath,amscd,concmath}
\pagestyle{empty}
\begin{document}
\begin{equation*}\prod_{No=1}^{\infty} \frac{(2no)^2}{(2no)^2-1} = \prod_{no=1}^{\infty} \frac{2no}{2no-1} \cdot \frac{2no}{2no+1} = \frac{\pi}{2}\end{equation*}
\end{document}
